nginx – 如果我们不关闭cgi.fix_pathinfo,服务器是否仍然容易受到攻击？

nginx安装附带的/ etc / nginx / sites-available / default文件具有以下内容：

# You may add here your
# server {
#   ...
# }
# statements for each of your virtual hosts to this file

##
# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# http://wiki.nginx.org/Pitfalls
# http://wiki.nginx.org/QuickStart
# http://wiki.nginx.org/Configuration
#
# Generally,you will want to move this file somewhere,and start with a clean
# file but keep this around for reference. Or just disable in sites-enabled.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
##

server {
    listen 80 default_server;
    listen [::]:80 default_server ipv6only=on;

    root /usr/share/nginx/html;
    index index.html index.htm;

    # Make site accessible from http://localhost/
    server_name localhost;

    location / {
        # First attempt to serve request as file,then
        # as directory,then fall back to displaying a 404.
        try_files $uri $uri/ =404;
        # Uncomment to enable naxsi on this location
        # include /etc/nginx/naxsi.rules
    }

    # Only for nginx-naxsi used with nginx-naxsi-ui : process denied requests
    #location /RequestDenied {
    #   proxy_pass http://127.0.0.1:8080;    
    #}

    #error_page 404 /404.html;

    # redirect server error pages to the static page /50x.html
    #
    #error_page 500 502 503 504 /50x.html;
    #location = /50x.html {
    #   root /usr/share/nginx/html;
    #}

    # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    #
    #location ~ \.php${
    #   fastcgi_split_path_info ^(.+\.php)(/.+)$;
    #   # NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini
    #
    #   # With php5-cgi alone:
    #   fastcgi_pass 127.0.0.1:9000;
    #   # With php5-fpm:
    #   fastcgi_pass unix:/var/run/php5-fpm.sock;
    #   fastcgi_index index.php;
    #   include fastcgi_params;
    #}

    # deny access to .htaccess files,if Apache's document root
    # concurs with nginx's one
    #
    #location ~ /\.ht {
    #   deny all;
    #}
}


# another virtual host using mix of IP-,name-,and port-based configuration
#
#server {
#   listen 8000;
#   listen somename:8080;
#   server_name somename alias another.alias;
#   root html;
#   index index.html index.htm;
#
#   location / {
#       try_files $uri $uri/ =404;
#   }
#}


# HTTPS server
#
#server {
#   listen 443;
#   server_name localhost;
#
#   root html;
#   index index.html index.htm;
#
#   ssl on;
#   ssl_certificate cert.pem;
#   ssl_certificate_key cert.key;
#
#   ssl_session_timeout 5m;
#
#   ssl_protocols SSLv3 TLSv1 TLSv1.1 TLSv1.2;
#   ssl_ciphers "HIGH:!aNULL:!MD5 or HIGH:!aNULL:!MD5:!3DES";
#   ssl_prefer_server_ciphers on;
#
#   location / {
#       try_files $uri $uri/ =404;
#   }
#}

你可以看到有一个注释“你应该有”cgi.fix_pathinfo = 0;在php.ini“.在它上面,我们也有这一行：

fastcgi_split_path_info ^(.+\.php)(/.+)$;

根据Security issue on Nginx,PHP & fastcgi_split_path_info后的帖子,我们可以通过关闭cgi.fix_pathinfo或使用fastcgi_split_path_info来缓解path info vulnerability.

既然它已经使用fastcgi_split_path_info指令来对抗这样的漏洞,为什么它仍然说我们应该关闭cgi.fix_pathinfo？如果我们不这样做,我们的服务器是否容易受到攻击？

最佳答案
Nginx wiki page on PHP-FPM配置建议打开cgi.fix_pathinfo.注意使用的正则表达式：

fastcgi_split_path_info ^(.+?\.php)(/.*)$;

该页面还提供了一个测试,您可以在其中访问下面列出的不同URL,并检查REQUEST_URI,SCRIPT_NAME,PATH_INFO和PHP_SELF的正确值.

/test.php
/test.php/
/test.php/foo
/test.php/foo/bar.php
/test.php/foo/bar.php?v=1 

test.php只包含<？php var_export($_ SERVER)？>.这有助于确定您的设置是否安全.在所有网址上,您的SCRIPT_NAME都应为test.php.无论如何,你不应该在那里看到bar.php.